Alternator

[bansheebuzz]

yes have aux battery, voltage stays up there load or no load

[Squid_87]

How do the 12v-12v chargers work? Im a little confused. Also, how do you work out what amp range you will need for the 12v-12v charger?

Thanks,
Luke

[rodw]

GUys this is aesome info and a lot cheaper than the Rotronics gear I saew at Opposite Lock today

[Squid_87]

GUys this is aesome info and a lot cheaper than the Rotronics gear I saew at Opposite Lock today

Have a few beers this evening Rod?

[pootrol]

How do the 12v-12v chargers work? Im a little confused. Also, how do you work out what amp range you will need for the 12v-12v charger?

Thanks,
Luke

spoke to dude today about the electro parts voltage booster one and told him i want to mount a large 4x4 battery in tray and he said a whole heap of complicated things but in general i could get away with a 20a but a 30 would be safer just to do one battery. all sorts of things about charging it to quike can start to cook the battery etc. you can go for the 40a but just by using an internal adjustment turn it down to about a 30. then in the future if you go to 2 batteries you can turn it back up and get the max from it. very interesting stuff as i didnt know about this until reading here and now im definately looking to get one...

[olcoolone]

pootrol, the dude you spoke to is correct regarding the amp output and limiting it.

A deep cycle battery was never designed for automotive use, they were designed for stand by power applications in a controlled environment so don't expect a deep cycle battery to work or last as long in an automotive application.

A bit about battery's first.... deep cycle battery's are rated in amp hours (75a/h, 100a/h, ???a/h), generally this is calculated usually with a small load from a 100% state of charge (SOC) until the battery reaches 10.5 volts or near flat depending on battery and who is doing the testing.

A 100 amp hour rated battery will deliver a 5 amp load for 20 hours when the battery will be classed as flat at around 10.5 volts (100 amp hours divided by 5 amps equals 20 hours use), using the 100 amp hour battery with a much lower current draw of 1 amp you might be able to get 110 hours of use (making it a theoretical 110 amp hour battery) , if you were using the same battery and you drew 25 amps per hour you might only get 3 and a bit hours out of it (making it a theoretical 75 odd amp hour battery).

Deep cycle battery's don't like high power demands and starting battery's don't like low power demands over a long period, think of a deep cycle battery as a marathon runner who will plod along hour after hour with no real problems but get him to sprint and he runs out of puff real quickly and takes a while to recover....A starting battery is like a sprinter who can deliver very high levels of energy very quickly for a short period of time and recover quickly but has no endurance.

This is why deep cycle battery's are rated in amp hours and starting battery's are rated in cold cranking amps.

There are some battery's that are a hybrid type that can sort of do both OK but not well (think amateur runner)

Rule of thumb- for true deep cycle battery's is to charge the battery no more then 15-25% of the total amp hours of the battery, if the battery is for example a 100 amp hour rated battery you could charge it up to 25 amps per hour.

Bear in mind a battery will last longer (in terms of life expediency) with a lower charge rate...for example if you charge a battery at 25 amps you may be able to do it 1000 times, if you did it a 10 amps you might be able to recharge it 1050 times before it need replacing.

In the real world we don't have to time to recharge a battery slowly hence the rule of thumb theory.

A good quality deep cycle battery will come or have available all spec regarding discharge rates and cahrge rates.

A starting battery can and will accept a higher rate of charge more reliably then a deep cycle battery, nearly all vehicles will only charge a battery up to 75% SOC....why?- keeps the battery condition better, is a reliable charge capacity for all environments and conditions, allows for compensation with heat and fluid levels and the biggest one is why does the battery have to be recharged to 100% SOC when the vehicle will start with in 10 seconds of cranking the engine helping the vehicle to get better fuel economy, less noise, less vibration and more power (alternators can take up to 5+KW's of power from the engine when under maximum load).

About DC-DC charges... a DC-DC charger can do what an alternator can't...charge the battery to 100% SOC at a higher voltage more suited to the battery (think of an alternator as the old type of battery charger and think of a DC-DC charger as a new age 3+ step smart charger.

Battery's and battery charging is such a hard thing to explain over the net and make it understandable.

Not all battery's and battery types are the same and suitable for all applications.

Not all deep cycle battery's are rated to the same standards.

Not all battery's are built the same in construction and quality.

You pay for what you get.




Sure I forgot something.

[rodw]

Olcolone, what an awesome description of diferent batteries, At my age, I am just a plodder but sometimes I manage 10 seconds of cranking but the charging interval seems to get longer with age....

[Alby]

This is a very informative thread. Thanks for the info guys.
My current setup has my auxilary battery in my tray with a redarc soloniod under the bonnet and 6mm2 wiring to the auxilary via an anderson plug. I have found that I never can get the battery fully charged and I thought it was because the cabling was too light to get enough amperage through and was going to upgrade it to 10mm2.
From what you are saying this will not fix the problem anyway???
Although is it correct that the battery will charge quicker with the 10mm2 cable upgrade??

Out of curiosity, what are all you blokes running that you need so many additional auxilary batteries???

[Squid_87]

I plan on doing trips of at least a week away so the fridge won't last that long on just one aux battery from my calculations

[Alby]

Olcolone, what an awesome description of diferent batteries, At my age, I am just a plodder but sometimes I manage 10 seconds of cranking but the charging interval seems to get longer with age....

Rod are you cranking or just fiddling with the positive terminal seeing if you can get a spark?

[Alby]

I plan on doing trips of at least a week away so the fridge won't last that long on just one aux battery from my calculations

I guess that depends on whether you are stationary the whole time or putting in some hours motoring in between?
With all that battery power would the alternator be able to recharge them all successfully??

When I was away up north we spent some time with an experience tourer who spends 6 months of the year on the road free camping at set spots for a week or more at a time .
He has two large solar panels as a helper but recons the best way to go is a 1kva honda generator that he runs for a couple of hrs a day with a 20 amp bttery charger.

[rodw]

Olcolone, what an awesome description of diferent batteries, At my age, I am just a plodder but sometimes I manage 10 seconds of cranking but the charging interval seems to get longer with age....

Rod are you cranking or just fiddling with the positive terminal seeing if you can get a spark?

That's me mate, just a fiddler!

Among all this stuff, what do the experts have to say about the Ctek battery chargers? Will say a 7 amp one gie us 100% SOC?

Been thinking of gettting a new battery charger to replace my 30 year old ARLEC 4 amp one so I don't succumb to Quiinny's "limp" problem and was wondering if a boost to 100% SOC before going away for a week was a good idea to keep the fridge cold...

[olcoolone]

Thicker battery cabling will help only if the size you are using is inadequate for you power demand, always use one size larger then what you really need as a minimum....bigger is better

A battery can have between 50 to 400+ amps of inrush current for a short period in some situations.

Alby, 10mm squared is still to small, the difference in price from that to 25mm squared is at the most maybe $60.00....do it right the first time.

We use 3B&S (25mm squared) cable as a bare minimum from the starting battery to the axillary battery then what ever is needed after that.

The 3B&S will power most things well plus you can use it for added power for winching or if you need to jump start plus it is still quiet flexible and easy to position.

We alway double insulate the positive cable with either split convoluted tubing or 12mm clear PVC tube, when using convoluted tubing make sure it is not touching anything that can't be rubbed through....we have seen it eat into high tensile truck chassis rails caused from vibration and not being secured properly.

We also try to cable tie or clamp the cables at no more then 100mm spacings.

Don't forget to fuse the cable at the starting battery, we use fuses in most applications over auto reset circuit breakers because if something is wrong you may not know as the circuit breaker will keep on resetting( you will find out when it's to late or your 200 kilometers away from someone who can repair it) where with a fuse it blows and you know straight away.

Luke what fridge have you got.

Heres a tip.....cut off the cigarette plug (and throw it as far as you can) on the end of your fridge power cable and join the remaining fridge power cable to 6mm sheathed twin core directly to the battery via a 10 amp fuse, this will eliminate the problem most people have with poor wiring and or cigarette plug and socket problems......when you want to remove the fridge just remove the power plug connected at the fridge it's self.

Everyone has there own Ideas of how it should be done.

Rod the Ctek is a good charger but a 7 amp one is to small, get the 25 amp as it also has a supply and rejuvenate mode.

It will charge you battery better and more reliably then your old charger.

Yes it will help your battery when going away, this is what we do.

We have just started selling the OZ Charge brand plus we sell Ctek.

[9W6VX]

Bloody good stuff.....

Thanks olcoolone for sharing.

Will be putting this in our upcoming bible ............. .

The electrical section is under Dave so he will be picking this up later to incorporate into our bible.

[Squid_87]

Luke what fridge have you got.

40 litre Engel. F series, purchased in September last yr. The 12v lead that comes with the Engel has a cigarette lighter plug on the end of it. It can be unscrewed and reveals a two pin threaded plug which plugs into an Engel hard wire socket, which also has about 6 inches of 4mm2 wire. Ive done this, then ran it back to an 8 gang fused block using 4mm2 then back to the battery via Anderson plugs (so I can remove the canopy) using 8B&S

[bansheebuzz]

In my vehicle i run a delkor 80ah battery using a 20a rated dc-dc charge system. i persolally would not go any higher than a 30a unit, you have to keep in mind the amount of load you can put on the alternator and for it to still charge the starting battery. i give example of my vehicle but keep in mind everones setup is often differant. these are approxamate amp ratings only an may not be 100% accurate

My car as follows
40amps high beam with spots (2X original and 4 100w spots)
20amp charge unit (maximum it regulates the current and will go to less than 1amp if battery charged)
10a engine electronics(at a guess)
10a ac on

There is 80 amps allready if im driving with the spots on, so if i went to a 40amp unit i would be overloading the alternator(100amp) if i used a 30amp then i would also over do it with a couple of other accessories on.


On cable size i do it depending on how the customer requires it, i do it like olocolone using 2b+s where the ability to manually override the isolator to crank off both batteries is required.

Also use 8B+s where the costomer does not want to spend the extra so the cable is suitable to charge the battery only(may run 6b+s if battery is mounted in rear or trailer). You can still jump off the battery with jumper leads.

[rodw]

Among all this stuff, what do the experts have to say about the Ctek battery chargers? Will say a 7 amp one give us 100% SOC?

Been thinking of gettting a new battery charger to replace my 30 year old ARLEC 4 amp one and was wondering if a boost to 100% SOC before going away for a week was a good idea to keep the fridge cold.

Any thoughts on this question guys?

[bansheebuzz]

rodw - go the multi xs15000, . If you trying to charge a dead flat cranking battery 7 amps is just too small. Trust me you will look back later and wish you bought a charger with a better output.

[crosssport]

I have the redarc smart charger and although it is only 5amp it works a treat. You dont want to bang heaps of amps in a battery quickly as this isnt good for charging or the life of the battery.
The redarc is a 4 stage charger and can save most batteries. As an example my boat battery has been sitting since january and only last week did I decide to start getting the boat tidied up and ready for some fishing. Yes the battery was dead. Removed the battery and connected the smart charger and nothing, cycle and then display faulty battery, turned off and on twice and then just left it there. Next day battery fully charged and no need to replace the battery.
Check out the specs on the redarc website. Rod I do believe the Cteck work in a similar way and are cheaper than the redarc unit.

Cheers
Shane

[olcoolone]

Crosspoint, we have a few of the Redarc 5amp smart charger for workshop use and are very good for small general automotive starting batteries but they don't cut it with most deep cycle types or large automotive starting ones.

The biggest problem is they have an inbuilt timer to limit charge times making them turn off on large battery's prematurely, this is an inbuilt safety feature to stop the charger being damaged.

They are brining out a larger one in the next three to four months for larger battery's.

The Ctek 25 amp is a fantastic charger (we have four of them) and we are testing the Oz Charge range of battery charges as we speak as they are cheaper then the Ctek.